Kirana said Lion Air, which previously threatened to cancel its order for 187 jets worth $21 billion at list prices, would need to be satisfied with the outcome of negotiations with Boeing before taking the planes.

"If they don't satisfy us, we will cancel the contract," he said.

All 189 passengers and crew on board one of Lion Air's new 737 Max jets died when the plane crashed into the Java Sea last October, the first of two deadly crashes that led to the craft being grounded worldwide.

A final report on the Lion Air crash is expected to be released at the end of September, Indonesia's civil aviation authority said last week.

Boeing is working to finalise a software fix of issues with an anti-stall system called MCAS that activated on the two crashed jets. Regulators will then need to approve the model's return to service before airlines take more of the planes.

Garuda Indonesia is also in talks with Boeing about changes to its order for 49 737 Max jets, its chief executive, Ari Askhara, told Reuters on the sidelines of an event to announce a maintenance joint venture with Lion Air.